a sensitive and selective method using combination of principal component analysis (pca), artificial neural network (ann) and uv-visible spectroscopy has been developed for the simultaneous determination of acetaminophen (amp) and codeine (cod) in plasma samples. the ann trained by the back-propagation learning was employed to model the complex non-linear relationship between the pcs extracted ...

water conveyance systems (wcss) are costly infrastructures in terms of materials, construction, maintenance and energy requirements. much attention has been given to the application of optimization methods to minimize the costs associated with such infrastructures. historically, traditional optimization techniques have been used, such as linear and non-linear programming. in this paper, applica...

BACKGROUND Many studies have examined the association between ambient temperature and mortality. However, less evidence is available on the temperature effects on coronary heart disease (CHD) mortality, especially in China. In this study, we examined the relationship between ambient temperature and CHD mortality in Beijing, China during 2000 to 2011. In addition, we compared time series and tim...

Analytical Solutions and type curves for the constant rate radial flow of fluid in both conventional and naturally fractured reservoirs including the effect of wellbore phase redistribution are presented. An automated procedure for non-linear least square minimization using the analytical solutions and their derivatives with respect to the unknown parameters developed to analyze the pressur...

In a hydroelectric power plant or in a pumping station in order to avoid sudden large increase of pressure due to instantaneous valve closure sometimes a surge tank is installed. The height of surge tank is designed by the highest possible water level during the operation. The theoretical treatment of oscillation in a surge tank is difficult because of the non-linearity of friction term in the ...

background and aim: it has been several decades since the technology of frequency lowering (fl) has been proposed. however, primary research has revealed no benefits regarding the use of this technique. currently, new methods for fl and improvement of perception of speech and fricative sounds have led to the application of these methods by numerous companies to produce hearing aids. in this stu...